Commenter Sparky reports, and the Oxford English Dictionary confirms: The term "taser" comes from "Tom Swift's Electric Rifle." "Yup, THAT Tom Swift," writes Sparky; "He had an electric rifle in a 1911 story."

Sparky (and Wikipedia) report that it comes from "Thomas A. Swift Electric Rifle" (Wikipedia: "The 'A' is gratuitous; the character's middle name was never provided"), though the OED doesn't say so.

Lasers were first described theoretically in the 1950s and first manufactured in the 1960s. So, unless the term appeared earlier in science fiction to describe other light emitting weapons, it seems that LASER (Light Amplification by Stimulated Emission of Radiation) was engineered to sound like TASER, and not vice versa.

So, unless the term appeared earlier in science fiction to describe other light emitting weapons, it seems that LASER (Light Amplification by Stimulated Emission of Radiation) was engineered to sound like TASER, and not vice versa

Tom Swift, back in 1911, didn't call his electic rifle a TASER. The guy who invented the TASER in the 1980's created the acronym based on Tom Swift and, possibly, looked to rhyme it with "Laser."
Besides, his only other options were TOSER, TUSER, TISER and TESER. Unless he was Welsh, in which case he could have gone for TWSER.

I used to love Tom Smith! As a preadoloescent, I thought Tom was far more interesting than those pansy Hardy Boys. I remember great titles like Tom Swift and his Jetmarine and Tom Swift and his Ultrasonic Cycloplane. I still have a dozen or so Tom Swift books on the shelf waiting for my sons (7 and 3) to get a little older.

"Set Phasers on stun!" Star Trek's writers called their guns Phasers because if they equipped the Enterprise's crew with Lasers, they'd get all these letters from scientists saying "Lasers can't do that!" And the capability of stunning someone without killing him is one one the things that lasers can't do.

I have a feeling that that's what the company was thinking about when they came up with Taser, but I'm also sure that it would be a bad idea for them to say so, since they'd hear from Gene Roddenberry's lawyers.